1. Field of the Invention
The present invention relates to a calculator capable, in response to an actuation of the addition or subtraction key, of executing addition or subtraction of the input numerical data with the contents of registers and storing the results of such addition or subtraction in the respective registers.
2. Description of the Prior Art
Consider the mathematical problem presented by the following: a wholesaler delivers merchandise x to the retailers A, B and C in the respective monetary amounts of xA, xB and xC, another merchandise y in the amounts of yA, yB and yC, and still another merchandise z in the amounts of zA, zB and zC. Prior art having required calculation of electronic devices the total sales amounts Sx, Sy and Sz of merchandises x, y and z and the total sales amounts T.sub.A, T.sub.B and T.sub.C of retailers A, B and C, separately according to the following equations: EQU Sx=xA+xB+xC, Sy=yA+yB+yC, Sz=zA+zB+zC, EQU T.sub.A =xA+yA+zA, T.sub.B =xB+yB+zB, T.sub.C =xC+yC+zC.
Moreover the grand total of the sales has had to be further calculated according to the equation S.sub.T =Sx+Sy+Sz or S.sub.T =T.sub.A +T.sub.B +T.sub.C, and these calculations require quite cumbersome operations.